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Radeon HD 4890 1GB vs Radeon HD 4890 2GB
Intro
The Radeon HD 4890 1GB comes with a GPU core clock speed of 1000 MHz, and the 1024 MB of GDDR5 memory runs at 975 MHz through a 256-bit bus. It also is made up of 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.Compare those specifications to the Radeon HD 4890 2GB, which has GPU clock speed of 1000 MHz, and 2048 MB of GDDR5 RAM running at 975 MHz through a 256-bit bus. It also is comprised of 800(160x5) SPUs, 40 TAUs, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Both cards have the same power consumption.Memory Bandwidth
Both cards have exactly the same memory bandwidth, so theoretically they should perform exactly the same. (explain)
Texel Rate
Both cards have exactly the same texel fill rate, so theoretically they should be equally good at at AF. (explain)Pixel Rate
Both cards have exactly the same pixel fill rate, so in theory they should perform equally good at at anti-aliasing, and be able to handle the same resolutions. (explain)
Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.
Price Comparison
Please note that the price comparisons are based on search keywords, and might not be the exact same card listed on this page. We have no control over the accuracy of their search results.
Radeon HD 4890 1GBAmazon.com
Other US-based stores
Amazon.co.uk
Amazon.de
Amazon.fr
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Radeon HD 4890 2GBAmazon.com
Other US-based stores
Amazon.co.uk
Amazon.de
Amazon.fr
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Specifications
| Model | Radeon HD 4890 1GB | Radeon HD 4890 2GB |
|---|---|---|
| Manufacturer | ATi | ATi |
| Year | Apr 2, 2009 | Apr 2, 2009 |
| Code Name | RV790 XT | RV790 XT |
| Fab Process | 55 nm | 55 nm |
| Bus | PCIe 2.0 x16 | PCIe 2.0 x16 |
| Memory | 1024 MB | 2048 MB |
| Core Speed | 1000 MHz | 1000 MHz |
| Shader Speed | N/A MHz | (N/A) MHz |
| Memory Speed | 975 MHz | 975 MHz |
| Unified Shaders | 800(160x5) | 800(160x5) |
| Texture Mapping Units | 40 | 40 |
| Render Output Units | 16 | 16 |
| Bus Type | GDDR5 | GDDR5 |
| Bus Width | 256-bit | 256-bit |
| DirectX Version | DirectX 10.1 | DirectX 10.1 |
| OpenGL Version | OpenGL 3.0 | OpenGL 3.0 |
| Power (Max TDP) | 190 watts | 190 watts |
| Shader Model | 4.1 | 4.1 |
| Bandwidth | 124800 MB/sec | 124800 MB/sec |
| Texel Rate | 40000 Mtexels/sec | 40000 Mtexels/sec |
| Pixel Rate | 16000 Mpixels/sec | 16000 Mpixels/sec |
Memory Bandwidth: Memory bandwidth is the maximum amount of data (counted in megabytes per second) that can be moved past the external memory interface in one second. The number is calculated by multiplying the interface width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.
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